Epitaxy refers to the deposition of a crystalline overlayer on a crystalline substrate, where there is one or more preferred orientations of the overlayer with respect to the substrate. The overlayer is called an epitaxial film or epitaxial layer. The term shallow trench isolation (STI) is another integrated circuit feature which prevents electrical current leakage between adjacent semiconductor device components. STI, generally used on CMOS process technology nodes of 250 nanometers and smaller, is created early during the semiconductor device fabrication process, e.g., before transistors are formed. The key steps of the STI process involve etching a pattern of trenches in silicon (Si), depositing one or more dielectric materials (such as silicon dioxide) to fill the trenches, and removing the excess dielectric.
A Fin-FET is a nonplanar or three-dimensional, multiple-gate transistor structure built on a Si or other substrate. The distinguishing characteristic of the Fin-FET is that the conducting channel is formed within a Si fin, which forms the body of the device. The length of the fin (measured in the direction from source to drain) determines the effective conductive channel length of the device. The conductive channel is the “stream” through which electrons flow from source to drain on the device. The fin structure can be formed by STI thin down or growing Si epi (epitaxial layer), e.g., in STI trenches.